Sportrak fuel tank pressure


Hi there,
New owner of a 93 Sportrak. I have a question in regards to the fuel tank. The last couple of times I've filled up, the fuel cap has been very difficult to remove. There is a very strong vacuum in the tank.

As the car's fuel gets low the vacuum pressure in the tank seems to get quite severe.

Is this normal????

Any advice is greatly appreciated.

P.S. I kind of bought this car on a whim. Clean body and started and drove like a car half its age, inspite of it 102K..... hoping this isn't going to get expensive.....

OK.... so nothing to worry

OK.... so nothing to worry about then. Thought it might cause undue stress on fuel pump.

Any ideas why this needs to happen?


It is the fuel tank breather which is blocked, corroded, or internally broken, this is a small plastic housing on a small bore pipe from the top of the tank.

Internally it is a small ball bearing with a spring either side to hold it central, as the fuel tank warms up, the fuel expands and this surplus pressure pushes the ball one way. When the tank cools it contracts and operates in reverse. Due to emissions legislation these were introduced to prevent fuel fumes from escaping from the tank.

Locate the breather pipe from the top of the tank, it will run to the body where the breather is mounted, remove the breather unit itself. Blow down the unit, then suck the unit, if no air passes it is blocked, spray penetrating oil into the unit to try to free it, if this works fine. If not it is another breather that is required.